CD274 and cancer: Given that the expression of PD-L1 on T cells and NK cells has been reported (55, 56), together with the blockade of PD-L1 on cancer cells by the 12C antibody, a direct effect of PD-L1 on T cells or other immune cells may also enhance the efficacy of the 12C antibody in the caninized PD-L1 mice in addition to the targeting of PD-L1 on cancer cells.